Fusible link.



FUSIBLE LlNK. APPLlcATxoN HLEU Auchxs, 19

Patented. Feb. 25,1919.

i embodying the therethrou h.

l but taken EDWARD F. SHIPMAN, 0F WOODHAVEN, NEW YORK.

FUSIBLE LINK.

Specification of Letters Patent.

Patented Feb. 25, 1919.

Application led August 18, 1917. Serial No. 187,000.

To all whom z't may concern.'

Be it known that I, EDWARD F. SHIPMAN, a citizen of the United States, residing in Woodhaven, county of Queens, and State of New York, have invented a certain new and useful Fusible Link, of which the following is a specification.

his invention is a fusible link adapted, more particularly, for use with automatic sprinklers, although not specifically limited to this application. The object of the invention is to provide a fusible link which will be extremely strong under tension and quickly disruptable upon the application of a predetermined degree of heat.

A further object of the invention is to improve upon links heretofore employed by so constituting the structure that the parts may be readily stamped up from sheet metal in a most economical and efficient manner.

With the foregoing objects in mind, the preferred embodiment of the invention which are united by fusible solder.I and between which members is positioned a keypiece in the form of a circular disk seated in correspondingly shaped depressions or pockets in the respective tension members. Spacing projections are preferably provided on the inner face of each member and are adapted to contact with the adjacent face of the other member to maintain said members in spaced relationv for the purpose of facilitating the assembling operation and the apfusible solder thereto. eatures of the invention, other than those specified, as well as the advantages thereof, will e apparent from the hereinafter detailed description taken in conjunction, with the accompanying drawing. l

In the accompanying drawing I have illustrated different practical embodiments of the invention, but the constructions therein shown are to be understood as illustrative, only, and not as defining the limits of the invention.

Figure l is a perspective view of a link present invention. Flg. 2 is a central, longitudinal section perspective view of the key- Flg. 3 is a and piece employed Figs. 4 and 5 are views like unto F ig. 2, through links of slightly modified constructions.

Referring to the drawing, A and A desigseats C C',

through these apertures are adapted to eX- tend chains, cables, or other devices which it is. desired that the link shall normally maintain in spaced relation at the point of application of the link. In order that the aperplate is provided at the end adjacent said aperture with a rentrant portion B, and plate A is similarly formed at its o posite end, so that chains or cables, passing t rough apertures with by the adjacent plates.

Positioned substantially centrally of plates A and A and formed in the adjacent surfaces thereof, are circular depressions or whereby, when the platesl are brought into juxtaposition, as shown in Figs. l and 2, a substantially circular chamber or space will be formed by the combination of the two pockets. In this chamber or space is positioned a key-piece'D, in the form of a metallic disk, shown in detail in Fig. 3.

The formation of the pockets C and C and the manner of their positioning in the plates A and A respectively, may vary, as shown in Figs. 2, 4 and 5. As shown in Fig. 2, the pockets C and C are, at their sides respectively adjacent opposite ends of the link, substantially equal in depth to the thickness of key disk D, and taper off in depth toward the opposite ends of the link, so that the faces of pockets C C intersect with the inner faces of plates A A', respectively, after the manner shown in Fig. 2. With this construction, key disk D, when positioned within the chamber formed by pockets -C and C', is tilted, relative to the aXis of the link, to an appreciable extent, one edge of disk D lying wholly within plate C d the diametrically opposite portion thereof lying wholly within plate C.

In F1 g. 1 complete, shown as impressed in the surface of both plates, the faces of said pockets lying entirely beneath the adjacent faces of the plates, and not intersecting therewith as in the construction of Fig. 2. 'Iche structure of packets of both plates, is not tiltedto such an appreciable extent as is the case in Fig.

cylindrical pockets arel a and a', will not be interfered 2, and greater tension Will be required to separate the plates after the solder has been melted. In otherv'vrds, While theY construe# tion of Fig. 2 may separate when thesolder has become softened, but not entirely melted, the structure of Fig. l W'll require that the slder become so'fter'before the link Willk be disrupted.

lnthe construction of Fig. 5, the pockets are shovvn as depiessedsquarely intov the respective plates; so that the faces of the pockets lieinplanes. parallel to'the faces of the" plates'.- lnsuch al censtruc'tiointhe key disk D@ vfv'illE not be tilted, but its faces Will be parallel to faces' of the pla-tese, While alink' of thisc'liaaifcter will withstand greater tension than the constructions of Figs; 2' ande, it will require that the solder befpractically melted before the link Will be disrupteds lt tvill, of coursegbe understood that the link is floated with fusible solder, and,v in order? to'facilitate the assembling and solderingfoperations, each" plate isprefer'ably provided?I with inwardly extending projections E formed by stamping out the' plates, as shownat' c. These `prejections serye to s ace the plates slightly apart, so-that the' e ges thereof' maybe properly soldered. ln the accompanying drawing', in" the interest of clearnes's', thleplates are shown as spaced an appreciable' distance apart, and considerable clearancevis'shown between the disk D and tliepoekets-wvh'ich liousethesamei lt will be unders'tedf' that, iny practice, this' space is muclr lessflthan as shown, the platesl being brought' into s" estantal'ly face-abutting relation;

An important consideration in the manufacture and use ofthe link of this invention resides" inVv the fact that the'pockets are formedf inl such' a manner that the edges o thereof'aresubstantially sharp edges. Ilvhe advantage loftliis construction is that, When assembled, tension* is applied to the link vvhich'positinslthe disk and'causes the outer or'sharpt edgesofthe pockets to gripA the disk on a lineflu'sh with theinner' faces of the plates'. By fhis*construction-the off-set and thickness; offthekey disk are' reduced to a minimum, forming a very rigid and strong censtructon. y l

The use of a circular disk is very important, in that4 practically the entire circumference of the disk carries the' tension on the pla-tes, sinfce substantially said entirefcircmfere'nce forms: a bearing surface which seats'in' thecbrrespondin parts of therespectivepockets': lhus, W en the plates are assembled, tlie disk a greater portion of its circumference' inY bearing Contact, but, the moment the link startsto separate, the bearing' istransferred tothe knife-like edges of the pockets' and a practically frictionless bearing" results. TheY disk. in this position.

' tive, flat is very unstable and is free to turn on its axis in rotary movement, or tilt upon its Y edges', so that it will open Will-readily overcome any ference, such as corrosion attacking one edge of the link and serving to hold the same stronger than the other edge thereof. In the' case ofv greater corrosion at one edge than the other, slight lateral or rotary movement of the disk' will resultduring the disruptioir of t f e parts, andV this Lmoment Will assisteinbreaking or overcoming such me` very quickly an chanical resistance;-

rnark'ed advantage' inherent in the use of 'al circular diskas akey-piece is the ease With Which the pockets may! be stamped through tlieuseof a circular die; l Such a die will allo'W ofy maximum depth Without any tendency to tearfor breaklthe plates; Through the :use of' a circulardisk,moreover, a much greater bearing surface, and consequently more complete distri"'c'ution`` of the load, result, and a stronger link may belmadefroni lighter material than could possibly' be the case in' suchA links asr employ elongated bars Which extendlongitudinally of theI link and carry the load at their ends, or similar bars whi' h extend transversely of Vthe-link; and only carry the load at their edges; The' positioning ofl the circular disk in the center of the link, where it is protected? from' theeflect of corrosion, is a marked advantage over linksemployfing'a tilting bar or cylindrical pin extending transversely o from face t'o'facer thereof, since, in tlielatter case, the" ends of thebar or pin'- areeX'po'sed te'the actionof corrosion the link will not yopen sofreely after the" so'l'd'erl has become softened.

lt" has heretofore been suggested to employ spherical key-pieces', and an" eXarnple of sach'const'rueton is shown in the patent to Perry, No. 17,208,200, Vvl'lierein the keypiece is in'the'forin of a ball bearing. v ln a construction of" this character, the solder carries substantially all' of the load, since the plates of theV link engage with' the rounded faces oftlieball and doxn'otseat inflat, Y

abutting contact with the key-piece, asis allev case with the presenty invention, VIt is necessary, in links embodying the ball'bearingkey-p'iece', to' provide some otherV means fer'strei'igthenin'g the link', andthisPerry acccrnplishesl by' means of bent-up ears which are adapted to be covered vvwith' solider. In contradstnctorr' to' the sldin'gv engagement between the"platesV and the" key-piece oft'l'i'e Perry patent, and other' priorf structures embodying the ball bearing" principle, tlie disk'of this inve 'tion' provides aV posix shoulder engagement which carries the load en the link, the' Solder serving only to maintainv thev plates against the tilting action of the key. The present invention thus embodies alltlrebenets of suchrotary mechanical intere are vlans and movement as are present in the ball bearing construction, without embodying the marked objectional features thereof, and is considerably stronger and will withstand far greater tension than links of the ball bearing type, while employing much less material and relying entirely upon the key-piece, to the exclusion of extraneous projections, etc.

Having thus fully described the invention, what I claim as new, and desire to secure by Letters Patent, is:

l. A fusible link embodying two complementary tension plates, each of which is provided in its inner face with a circular depression or pocket, said depressions being adapted to register with eachother when the plates are placedk in lapped relation, whereby a circular chamber is formed between the plates, a circular disk occupying said chamber, and fusible solder uniting the tension plates.

2. A fusible link embodying two lapped tension plates, a circular disk housed between said plates and within circular depressions formed in the inner faces of said plates, and fusible solder uniting said plates.

3. A fusible link embodying two lapped members, each of which is provided with a circular depression, said depressions registering to form a substantially closed, rela- Copies of this patent may be obtained for ve cents each, by addressing the tively shallow, circular chamber, a circular disk occupying said Chamber, and fusible solder uniting the plates.

l. A fusible link embodying two lapped tension plates, a flat circular disk housed within depressions formed in the inner faces of said plates, said depressions intersecting with the inner faces of their respective plates to form sharp edges, and fusible solder for uniting the lates, whereby, when the solder is melted, t e plates swing apart on the disk, employing said sharp edges as fulcrums.

5. A fusible link embodying a pair of lapped tension plates, each of which is provided with a circular depression having sharp edges, said depressions registering to form a substantially closed,'relatively shallow, circular chamber, a Hat circular disk occupying said chamber, and fusible solder uniting the plates, whereby, when the solder is melted, the disk tilts and the plates swing apart, with the circumference of the disk bearing on the sharp edges of the pockets,

the disk being free to turn on its axis during the tilting operation of said disk.

In testimony whereof I have signed my name to this specification.

EDWARD F. SHIPMAN.

Commissioner of Patents,

Washington, D. C. 

